Why Drain A Lake?
Posted: 22nd Jan 2014
I have had a breather today while tidying the lakes up and removing all the equipment used on the drain down.The weather has taken a huge nose dive today with a very hard frost and temps down to -4 this morning. It has been a very wet 12 months as you all know back in Blighty, which has made it a very messy job over the winter. I guess a lot of people wonder why I bother to drain the lakes so I will give you a rough idea what it has entailed and why all the hassle!!
The aim is to provide the Carp in the lake with optimum conditions for growth and health while maintaining the equilibrium of the whole Biomass. This is the stock level for the total volume of water which has to be monitered otherwise other species can breed so prolific, pushing the biomass to its maximum level which can lead to water quality problems and reduced growth rates. Predator fish play a vital role in maintaining a healthy stock level, but with such a large stock of Carp it's very difficult for them to keep the small Carp numbers down, and in our case mostly Tench. We don't have too many young Carp fry surviving but the Tench can breed in numbers which all need feeding, thus exhausting natural food stocks which could be benefical to the Carp.
This season my aim was to drain both lakes and pump the last 12" of water out of the 7 acre lake to remove all the Tench. It's the most resilient species I have ever encountered, and regardless of how well you sweep the net they bed down hard in the soft clay bed and avoid capture, with this in mind my aim was get all the water out so they have no place to hide and it worked a treat!!
With the big lake split in two while I carry out the work, the stock have lived on one side all season, while I excavated the far bay and transferring the stock over the spit into the completed side. This left me with one half of the 15 acre lake empty, so it was refilled and the 7 acre lake was then drained. The stock from the 7 acre had to be transferred into the empty side of the 15 acre lake for a month while I aimed to drain the smaller lake completely and remove all the fish, it all sounds complicated hey!! By carring out the work in this fashion I could take my time working on the 7 acre lake without stressing about the Carp stocks health, allowing me to complete the task over Christmas while still feeding the fish stress free on the near side of the large lake. With the pump running for two weeks I removed all but a puddle in front of the monk and even I was amazed how many fish where removed. 880lb of Tench were removed along with 1000lb of Roach & Perch. 50+ Pike & 100 Zander were put to one side, together with the Carp stock. This gives you an idea of the shear scale of fish harvested, with the 15 acre lake producing twice this weight!!!
All the Tench apart from a dozen of the very best being kept to around 8lb, 200 Zander and 100 blackbass will be added for this year, along with the most stunning stock of 100 Roach to 2.5lb. I guess you might ask why return other fish at all and not just keep the Carp, but it's vital to maintain a balanced stock of species which benefit the whole ecosystem, and maintain the health of the lake along with the Carp. I have reduced the Grass carp down to 35 large ones, mostly 30lb+ up to low 40lb. All the low 20lb grassies were sold and replaced with 35 young low-mid doubles. When the grassies are young they are an eating machine, eating their body weight per day, but as they become older their metabolism slows down and they seem to spend most of their time sunbathing and not eating weed. The weed situation has never been an issue after adding them, so it's vital I maintain a stock of Grassies to keep the weed in check and not prevent an issue for the anglers.
Along with the Grassies I have returned a stock of 155 carp with approx a 3rd of the fish being between 40lb-55lb. The remaining stock is mostly 30lb+ with some stunning 20lb+ young scaley fish for the future. I always keep a stock of smaller fish to around mid to upper double, which again are young fish for growing on. It's good for them to be aclimatized to the lake at such a young age to help them build a good immune system. Only 30 of these fish are present, so on average only a couple will show each week throughout the season, and will not be counted in the catch reports. So the stock stands at 190 big Carp and Grassies, along with 30 smaller Carp and 35 smaller Grassies taking the total head count to 255 fish.
This will be monitored over the next 3 years to allow continued growth rates, and we should start to see the highs reached a couple of years ago with fish nearly touching the 60lb barrier.
I will start loading pictures each night on facebook of some of the stock, the pictures are not all perfect poses, as you can appreciate the health of the fish is paramount and photographing this many fish is just an impossible task when you have your entire stock sitting in 2 feet of water in bitter conditions. When the rain stopped we took pics, my gormless face says it all, tired, cold and just wanted to get the job finished. So there are all kinds of shots from fish slapping my face, to Grassies jumping over my shoulder, one fish, one picture, and when they jump out of your hands, tough!!!! No second chances.
All in all it's been a fantastic success, and with nearly 2000lb of fish removed I hope to see some amazing weight gains this summer, talking of summer I cannot wait.